pediatric lateral condyle fractures are the second most common fractures in the pediatric elbow and are characterized by a higher risk of nonunion, malunion, and AVN than other pediatric elbow fractures.
treatment is dictated by the degree of articular displacement and may require CRPP or open reduction.
Epidemiology
incidence
17% of all distal humerus fractures in the pediatric population
2nd most common elbow fracture after supracondylar
demographics
typically occurs in patients aged 6 years
location
most commonly are Salter-Harris IV fracture patterns of the lateral condyle
Pathophysiology
mechanism of injury
pull-off theory
avulsion fracture of the lateral condyle that results from the pull of the common extensor musculature
push-off theory
fall onto an outstretched hand causes impaction of the radial head into the lateral condyle causing fracture
pathoanatomy
fractures originate proximally at the posterior aspect of the distal humerus metaphysis and extend distally and anteriorly across the physis and epiphysis into the elbow joint
fracture may extend medially into the trochlear groove, making the elbow unstable and prone to dislocation
Prognosis
outcomes have historically been worse than supracondylar fractures
articular nature, missed diagnosis, and higher risk of malunion/nonunion
Anatomy
Ossification centers of elbow
lateral (external) epicondyle
ossifies/appears at age 11 years
fuses at age 12-14 years
age of ossification/appearance and age of fusion are two independent events that must be differentiated
Ossification center
Years at ossification (appear on xray) (1)
Years at fusion (appear on xray) (1)
Capitellum
1
12-14*
Radius
3
14-16
Internal (medial) epicondyle
5
16-18
Trochlea
7
12-14*
Olecranon
9
15-17
External (lateral) epicondyle
11
12-14*
(1) +/- one year, varies between boys and girl. C-R-I-T-O-E to remember age of ossification. CTE-R-O-I to remember age of fusion (capitellum, trochlea and external (lateral) epicondyle fuse together at puberty. Together they fuse to the distal humerus between the ages of 14-16 years old)
Blood Supply
the brachial artery lies anteriorly in the antecubital fossa
most of the blood supply of the distal humerus comes from the anastomotic vessels that course posteriorly
Classification
Milch Classification-controversial
Type I
Fracture line is lateral to trochlear groove (less common, elbow is stable as fracture does NOT enter trochlear groove)
Type II
Fracture line extends medially into trochlear groove (more common, more unstable)
Fracture Displacement Classification-Weiss, et al
Type 1
<2mm, indicating intact cartilaginous hinge
Casting
Type 2
>2 mm < 4 displacement, intact articular cartilage on arthrogram
Closed reduction and fixation
Type 3
>4 mm, articular surface disrupted on arthrogram
Open reduction and fixation
Presentation
History
fall onto an outstretched hand
Symptoms
location
lateral elbow pain and swelling
severity
may be subtle if fracture is minimally displaced
Physical exam
inspection
exam lacks the obvious deformity often seen with supracondylar fractures
swelling and tenderness are usually limited to the lateral side
lateral ecchymosis implies a tear in the aponeurosis of the brachioradialis and signals an unstable fracture
motion
may have increased pain with resisted wrist extension/flexion
may feel crepitus at the fracture site
Imaging
Radiographs
recommended views
AP, lateral, and oblique views of elbow
internal oblique view most accurately shows fracture displacement because fracture is posterolateral
optional views
contralateral elbow for comparison when ossification is not yet complete
routine elbow stress views are not recommended due to pain and lack of useful information
findings
fracture fragment most often lies posterolateral which is best seen on internal oblique views
in displaced fractures, the capitellum is laterally displaced in relation to radial head
posteriorly based Thurston-Holland fragment on the lateral view
Arthrogram
indications
minimally displaced fractures
to assess cartilage surface when there is incomplete/absent epiphyseal ossification
allows dynamic assessment
CT scan
indication
rarely indicated, only if there is uncertainty as to the type of fracture
MRI
indication
provides the ability to assess the cartilaginous integrity of the trochlea
useful for operative planning of delayed or non-unions
expensive
require GA/sedation to perform the test
arthrograms generally preferred to MRI
Differential
Pediatric Elbow Injury Frequency
Fracture Type
% elbow injuries
Peak Age
Requires OR
Supracondylar fractures
41%
7
majority
Radial Head subluxation
28%
3
rare
Lateral condylar physeal fractures
11%
6
majority
Medial epicondylar apophyseal fracture
8%
11
minority
Radial Head and Neck fractures
5%
10
minority
Elbow dislocations
5%
13
rare
Medial condylar physeal fractures
1%
10
rare
Treatment
Nonoperative
long arm casting x 4-6wks
indications
only if < 2 mm displacement in all views
medial cartilaginous hinge must remain intact
technique
cast with elbow at approx 90 degrees as long as swelling is mild
weekly follow up and radiographs every week x first 3 weeks, including internal oblique view
occasionally > 6 weeks of casting is needed
Operative
CRPP + 3-6 wks in above elbow cast
indications
fractures with 2 - 4 mm of displacement have intact articular cartilage and can be treated with CRPP
open reduction and fixation + 3-6 wks in above elbow cast
indications
> 4mm of displacement
open reduction (rather than closed) necessary to align the joint surface
joint incongruity
fracture non-union
supracondylar osteotomy
indications
deformity correction in late-presenting cubitus valgus - rarely needed
Techniques
CRPP
approach
closed reduction perhaps aided by pushing the fragment anteromedially to close the gap
instrumentation
divergent pin configuration most stable
screw considered for more rigid fixation
allows early motion
compresses fracture site
complications
pins are less stiff
screw may need to be removed if crossing the physis
ORIF
approach
anterolateral approach as blood supply comes from posteriorly
soft tissue
below the skin, dissection to the joint is most often already accomplished by injury
avoid dissection of the posterior aspect of lateral condyle (source of vascularization)
bone work
directly visualize the joint reduction, at times the metaphyseal reduction may not be perfect, as fracture fragment may have plastic deformation
instrumentation
most fractures can be fixed with 2 percutaneous pins (3 if comminuted) in parallel or divergent fashion
single screw for large fragments or non-union. bone grafting rarely needed
complications
pins are less stiff
screw may need to be removed if crossing the physis
Complications
Stiffness
incidence
most common complication
risk factors
stiffness may be an early sign of a non-union or delayed union
treatment
usually self-resolving
by 24 weeks 90% of motion returns and full motion is present by 48 weeks
Delayed Union
fracture that does not heal with 6 weeks of immobilization
risk factors
fracture that is seen more than 2 weeks after injury
treatment
may be treated with immobilization if minimally displaced
surgical treatment if displaced
must be followed until radiographic union as nonunion is common in this scenario
Nonunion
incidence
higher rate of nonunion than other elbow fractures
risk factors
nonsurgical management
mechanism - theoretical
constant motion at fracture site from pull of the wrist extensors